Na_xV₂O₅·yH₂O have been considered to be very promising electrode materials in the energy storage field by virtue of their V⁴⁺/V⁵⁺ mixed valences and co-intercalated Na⁺/H₂O. However, the as-reported Na_xV₂O₅·yH₂O usually present the low content of Na⁺ and the anisotropy of Li⁺ diffusion in the plane direction. Herein, we successfully synthesize a tetragonal NaV₂O₅·H₂O nanosheets co-intercalated by high content of Na⁺ and H₂O via a simple one-step hydrothermal method under broad synthesis conditions, where S^2- reductant has been proved to be very significant for its successful synthesis. With the synergistic effect of the isotropy of tetragonal lattice in the plane direction, and the co-intercalated high content of Na⁺ and H₂O, NaV₂O₅·H₂O nanosheets as anode material for lithium-ion batteries exhibit excellent electrochemical performance. The initial discharge and charge capacities are up to 859 and 607 mA h g⁻¹ at 100 mA g⁻¹, and the capacity is maintained at 473 mA h g⁻¹ after 500 cycles, which are outperform other reported layered sodium/lithium vanadate, lithium titanate, lithium/titanium niobate and graphite. In addition, we also reveal that the active material during cycling process is the Li_xNa_yV₂O₅·H₂O with stable crystal structure and morphology, and the Li⁺ storage process is coequally determined by diffusion and pseudocapacitive behavior.

Na _x V ₂ O ₅ · y H ₂ O由于它们的V ⁴⁺ / V ⁵⁺混合价和Na ⁺ / H ₂ O的共嵌入，在能量存储领域被认为是非常有前途的电极材料。因此，如所报道的，Na _x V ₂ O ₅ ·yH ₂ O通常表现出低的Na ⁺含量和Li ⁺在平面方向上的扩散各向异性。在这里，我们成功地合成了四方NaV ₂ O ₅ ·H ₂在宽泛的合成条件下，通过简单的一步水热方法，通过高含量的Na ⁺和H ₂ O共嵌入O纳米片，其中S ^2-还原剂已证明对于其成功合成非常重要。借助四方晶格在平面方向上的各向同性的协同效应以及Na ⁺和H ₂ O的共嵌入高含量，作为锂离子电池负极材料的NaV ₂ O ₅ ·H ₂ O纳米片表现出优异的电化学性能性能。初始充放电容量高达859和607毫安ħ克^-1在100mA克^-1，在500次循环后，容量保持在473 mA h g ^-1，优于其他报道的层状钒酸钠/钒酸锂，钛酸锂，铌酸锂/钛和石墨。此外，我们还发现，循环过程中的活性物质是具有稳定晶体结构和形态的Li _x Na _y V ₂ O ₅ ·H ₂ O，而Li ^+的存储过程由扩散和拟电容行为共同确定。